<?php
// pass by reference 

function addTwoElement(&$n1, $n2){
	$n1 = ($n1 + $n2);				// change the arg1
	echo $n1;
}

$arg1 = 100 ;		
$arg2 = 200 ; 
echo addTwoElement($arg1, $arg2),"<br>";
echo "arg1 = $arg1 is not 100. "; 
?>